Question

A variable star is one whose brightness alternately increases and decreases. Lists of variable stars can
be found online, and many occur in familiar constellations visible with the naked eye. One such star, R
Hydrae, has an average magnitude rating of 7.2 but its magnitude varies by ±3.7 between its maximum
and minimum brightness. The period between two consecutive instances of maximum brightness (the
period) for R Hydrae is 389 Earth days. Design a function M(t) that models the brightness of R Hydrae
as a function of time.